Unconventional field-effect transistor composed of electrons floating on liquid helium

TL;DR

This paper introduces a novel macroscopic field-effect transistor made of electrons on superfluid helium, enabling unique charge control and revealing negative source-drain current through collective electron behavior.

Contribution

It demonstrates a new type of FET using electrons on helium, allowing unprecedented control over charge density and collective electron phenomena.

Findings

Realization of unique transport regimes in the device

Observation of negative source-drain current

Control of charge density via collective electron behavior

Abstract

We report on an unconventional $macroscopic$ field effect transistor composed of electrons floating above the surface of superfluid helium. With this device unique transport regimes are realized in which the charge density of the electron layer can be controlled in a manner not possible in other material systems. In particular, we are able to manipulate the collective behavior of the electrons to produce a highly non-uniform, but precisely controlled, charge density to reveal a negative source-drain current. This behavior can be understood by considering the propagation of damped charge oscillations along a transmission line formed by the inhomogeneous sheet of two-dimensional electrons above, and between, the source and drain electrodes of the transistor.